(CNSNews.com) – The situation facing the planet because of climate change is “as dangerous” as the possibility of war over Iran’s nuclear activities, Sen. John Kerry (D-Mass.) told the U.S. Senate on Wednesday.

Delivering what his office described as “a major address and current assessment of the global climate change challenge,” Kerry acknowledged and bemoaned the success of those who question the notion of human-induced global warming. He compared skeptics to flat-earthers and decried what he called a “concerted assault on reason.”

“I believe that the situation we face, Mr. President, is as dangerous as any of the sort of real crises that we talk about – today we had a hearing in the Foreign Relations Committee on the subject of Syria, and we all know what’s happening with respect to Iran, and nuclear weapons and the possibility even of a war,” Kerry said.

“Well, this issue [climate change] actually is of as significant a level of importance, because it affects life itself on the planet,” he said.

Kerry said the term climate change had become “an unusable word in American politics.”

“Climate change, over the last few years, has regrettably lost credibility in the eyes and ears of the American people, because of a concerted campaign of disinformation – a concerted campaign to brand the concept as somehow slightly out of the mainstream of American political thinking.”

“I have to say it’s been a remarkably effective campaign, you can’t sit here and say it hasn’t worked,” Kerry conceded. “Every opportunity to cast a pall on facts with some kind of cockamamie theory has been taken advantage of, and a lot of money has been spent, Mr. President, a lot of money has been spent in this process of disinformation and of discrediting.”

“We have in effect, with respect to climate change in America today, what is fundamentally a flat-earth caucus, a bunch of people – some of them within the United States Congress itself – who still argue, against all the science, all the evidence, they argue that somehow we don’t know enough about climate change, or they argue that the evidence isn’t sufficient, or they argue that it just is a hoax.”

Kerry did not name his congressional targets, but earlier in the day, during a Senate Environment and Public Works Committee hearing, ranking member Sen. James Inhofe (R-Okla.) declared that “the global warming movement has completely collapsed and cap-and-trade is dead and gone.”

Inhofe was referring to the Waxman-Markey cap-and-trade bill, which sought to set up a system to limit and trade the emission of carbon dioxide (CO2) and other “greenhouse gases” blamed for climate change. The measure passed in the U.S. House in June 2009 by a margin of just seven votes, but died in the Senate.

Noting that the committee had not held a hearing on “global warming science” since early 2009, Inhofe said, “I suspect a look back over the past three years will be a little painful for some.”

Back then, with a Democratic president in the White House and Democratic majorities in the House and Senate, “the global warming alarmists were on top of the world – they thought they would reach their goal.”

Inhofe attributed the failure to “Climategate,” the scandal triggered by the leaking of emails revealing the apparent manipulation of data by some scientists linked to the U.N. Intergovernmental Panel on Climate Change (IPCC).

After reading excerpts of several articles critical of the IPCC from “publications that were on the alarmist side of this issue,” including the New York Times, Inhofe asked, “just how unpopular is the global warming movement now?”

“The Washington Post recently published a poll revealing that Americans no longer worry about global warming and one of the reasons is that they don’t trust the scientists and their motives,” he added.

In the poll, 18 percent of respondents identified “global warming/greenhouse effect/climate change” as the biggest single environmental problem facing the world, down from 25 percent in 2008 and 33 percent in 2007. Twenty-nine percent of respondents identified pollution as the biggest problem.

‘A whole lot of people are getting angry about this’

Wednesday’s 35-minute floor speech was the second time in two days that Kerry raised the issue on Capitol Hill.

He did so on Tuesday, when the Commerce Committee approved a bipartisan bill preventing U.S. airlines from participating in the European Union’s emission-trading scheme (ETS).

The E.U.’s seven year-old cap-and-trade system, which was extended to the aviation sector as of January 1 this year, charges all airlines entering European airspace for CO2 emissions, calculated not just while the aircraft is over Europe but over the duration of the entire flight.

The bill was introduced by Sens. John Thune (R-S.D.) and Claire McCaskill (D-Mo.) last December, two months after the U.S. House passed similar legislation, requiring the Transportation Secretary to prohibit U.S. carriers from participating in any ETS unilaterally set up by the E.U.

The Senate measure was passed Tuesday after amendments were made, at the behest of Kerry and Sen. Barbara Boxer (Calif.), requiring U.S. officials to pursue a global aviation emissions agreement, through the International Civil Aviation Organization.

“Because of the compromise language that Senator Thune was willing to accept, I think we’re in a good position,” Boxer told the committee. “We ‘re saying no to a unilateral move by Europe but yes to taking a lead role in [global] negotiations.”

Immediately after the vote, Kerry delivered an impromptu 13-minute speech in which he agreed the E.U.’s actions were “unacceptable,” but said the Europeans were “acting out of pure frustration,” given the stance of the U.S. and China, the world’s two biggest emitters.

“A whole lot of people are getting angry about this,” he said. “They ought to be.”

“We can’t pretend that just passing this thing is going to be the end of it,” he said. “We’ve got to have an international agreement, and all of us are going to have to step up and help lead in the United States, by doing some of the thing that we’ve avoided for 20-plus years that are staring us in the face.”

Thune urged the full Senate to pass the legislation immediately: “Congress must act to protect America’s sovereignty and ensure that U.S. operators and passengers are not penalized by this illegitimate tax.”

On Tuesday and Wednesday the administration hosted a meeting with representatives from 17 countries that also oppose the E.U. directive.